Search PubMed⌕ Search

Biomedical subjects

H Takano

Publications and source records attributed to H Takano.

At least 433 records · Page 24Linked to original sources
PubMed1989

Analysis of acute and chronic heart failure in view of hepatic oxygen supply-demand relationship using hepatic venous oxygen saturation.

The adequacy of hepatic circulation in terms of oxygen supply-demand relation was assessed by measuring hepatic venous oxygen saturation (Shvo2) in patients. Among those with congenital cardiac lesions (n = 11), Shvo2 during the early postoperative period was markedly low as less than 20% in Fontan operation group (n = 5) with subsequent clinical findings of acute hepatic dysfunction. Significant correlations were found between Shvo2 values early after surgery and subsequent peak values in serum hepatic enzymes. Serum total bilirubin and prothrombin time started to deteriorate when Shvo2 became below 30%. Cardiac index, hepatic perfusion pressure and mixed venous oxygen saturation showed positive linear correlations with Shvo2, and central venous pressure (CVP) with an inverse relation. In chronic valvular disease (n = 28), those with NYHA class IV patients showed lower Shvo2 (average; 47.4%) at cardiac catheterization than the others (class-I; 66.4%, class-II; 63.9%, p less than 0.05). These results indicate that Shvo2 monitoring appears to be useful to assess the hepatic perfusion in terms of oxygen supply-demand relation in acute and chronic heart failure, and Shvo2 of 30% seems to be a critical level.

Adult↗
PubMed1989

Early degeneration of the epithelial cells in the initial segment of the epididymal duct in mice after efferent duct cutting.

Mouse epididymides were examined by light and electron microscopy 6, 12, 24 h, 1.5, 2, 3, and 5 days after efferent duct cutting when the mice were 60 days of age. Six hours after operation, the principal cells in the initial segment of the epididymal duct began to degenerate following the disappearance of intraluminal spermatozoa. The degenerated cells increased rapidly and reached their greatest number 24 h, and then decreased to smaller numbers until 48 h. These degenerative changes were followed by the appearance of macrophages in the epithelium, which were first seen 12 h after operation, becoming very frequent at one and 1.5 days, and then decreasing to become rare at 3 and 5 days. The macrophages phagocytosed the degenerated principal cells. The degenerated principal cells were also ingested and digested by undegenerated principal cells and basal cells. The intraepithelial mitotic figures had almost disappeared at 24 h but were frequently observed at 2 days and more so at 3 days. They returned to normal numbers at 5 days. The volume of the initial segment was decreased to one third until the third day. The principal cells in this segment became similar in both light-microscopic appearance and ultrastructures to the cells in the next segment 5 days after efferent duct cutting. The changes were localized only in the initial segment.

Animals↗
PubMed1989

Cytological response of the principal cells in the initial segment of the epididymal duct to efferent duct cutting in mice.

The principal cells in the initial segment of the mouse epididymal duct were observed by light and electron microscopy over a period from 6 h to 4 weeks after efferent duct cutting. These were compared with the cells in Segment II (the segment next to the initial segment), in order to understand the functional differentiation of both segments. In the initial segment, a large number of the principal cells were degenerated and disappeared within 2 days after the operation. The remaining epithelial cells rapidly decreased in height as the degeneration proceeded and the principal cells were light- and electron-microscopically transformed into the cells similar to the principal cells in Segment II. The principal cells in Segment II showed no changes after efferent duct cutting. The findings suggest that the principal cells in the initial segment have a secretory potentiality of Segment II cells, which is normally latent but becomes manifest after the efferent duct interruption that removes the absorptive function of the testicular fluid.

Animals↗
PubMed1989

Evaluation of microencapsulated islets in agarose gel as bioartificial pancreas by studies of hormone secretion in culture and by xenotransplantation.

Islets were microencapsulated in agarose gel for examination of the possible use of microencapsulated islets as a bioartificial pancreas. Microencapsulated islets secreted insulin into the culture medium (RPMI-1640) and could rapidly increase their insulin release in response to a glucose challenge even after greater than 100 days. Hamster islets in groups of 400-1000 encapsulated in microbeads containing 11-14% (wt/wt) agarose were xenogenically transplanted into the peritoneal cavity of five diabetic mice. The longest normoglycemic period in these mice was 53 days, which was markedly longer than the normoglycemic period obtained by nonencapsulated islets. Agarose seems to be a suitable basic material for encapsulating islets, because the islets can easily be microencapsulated without any adverse effect on the islet function.

Animals↗
PubMed1989

Role of lipid peroxidation and oxygen radicals in compound 48/80-induced gastric mucosal injury in rats.

Repeated administration of a small dose of compound 48/80 induced acute gastric mucosal injury in rats. Thiobarbituric acid (TBA) reactants in the gastric mucosa were significantly increased and serum alpha-tocopherol was significantly decreased after the treatment. The total area of gastric lesions and the increase in TBA reactants in the gastric mucosa were significantly reduced by pretreatment with superoxide dismutase (SOD) and/or catalase, allopurinol and anti-rat polymorphonuclear leukocytes (PMN) antibody. Lipid peroxidation and oxygen radicals derived from both the xanthine-xanthine oxidase system and PMN may be involved in the pathogenesis of compound 48/80-induced gastric mucosal injury.

Animals↗
PubMed1989

Evaluation of thyroid scintigraphy in small animals.

Thyroid scintigraphy in rats and mice with 99mTc and 123I was attempted to examine whether this modality might be used in small animals and to describe the possibilities of its application in examining experimentally produced thyroid diseases. A human gamma camera with a pinhole collimator improved for small animals was used for imaging. Thyroid images with 99mTc were obtained 20 minutes after injection and those with 123I were 24 hours after administration. All the scintigrams, although those obtained from mice with 99mTc displayed overlapped salivary gland images, demonstrated sufficiently clear images in size and shape, which showed that thyroid scintigraphy in small animals should be applicable in examining experimentally produced thyroid diseases.

Animals↗
PubMed1989

[Histochemical study on glutathione S-transferase in patients with testicular tumor].

Tumor tissue and nontumorous tissue of 31 patients with testicular tumor were examined by the peroxidase antiperoxidase (PAP) procedure using the primary antibody against glutathione S-transferase (GST). Histology of primary tumor was classified as seminoma in 10 cases, non-seminoma in 18 (including 2 cases of yolk sac tumor), and malignant lymphoma in 3. Tumorous tissues except one with yolk sac tumor failed to be stained with GST. The seminiferous tubules of the nontumorous testicular tissue had a positive reaction in the infant cases, but not in the adult cases. The degenerated seminiferous tubules involved in the testicular tumors also had a positive reaction in all the cases. Leydig cells had a positive reaction in all the cases. In particular, diffuse Leydig cell's hyperplasia was observed in a case with high serum beta hCG and urinary hCG levels. These data may be relevant in explaining the inherent hypofertility of these patients.

Adult↗
PubMed1989

[Chemoembolization with degradable starch microspheres for liver metastases in colorectal cancer].

Transcatheter chemoembolization using Degradable Starch Microspheres (DSM) was performed in 17 patients with liver metastases of colorectal cancer. Mitomycin C mixed with DSM was injected into the proper hepatic artery. Tumor regression of over 50% was observed in 9 of 17 cases (53%). Elevated serum CEA levels (greater than 10 ng/ml) decreased in 10 of 15 cases (67%). One-year survival rate was 50% in 17 cases. One-year survival rate was 100% in 7 cases with several liver metastases (H2). Abdominal pain occurred in 36%, mostly disappearing within 2 hours. No major side effects such as bone marrow suppression or hepatotoxicity were observed. Our results suggest that chemoembolization using DSM is effective and safe in the treatment of liver metastases from colorectal cancer.

Colorectal Neoplasms↗
PubMed1989

[Healing process of bone fractures examined with X-ray radiography and xeroradiography].

The healing process of bone fractures produced in rat mandibulae was examined with conventional X-ray radiography and xeroradiography. Sixty rats of about 200g were offered to this examination and fractures were experimentally produced in the right mandibulae. Radiological observations were carried out immediately, 1 day, 4 days, 7 days, 14 days, 21 days, 28 days, 35 days, 42 days, 49 days and 56 days after fracturing. The conventional X-ray radiograms showed no noteworthy changes until the 4th day after fracturing. The radiopacity gradually increased from the 7th Day until the 56th day. The xeroradiograms obtained on the 4th day showed some early changes which appeared on the periosteal regions of the right mandibulae. The calcification of fractured regions on the xeroradiograms gradually increased until the 56th day, similar to that observed on the conventional X ray radiograms.

Animals↗
PubMed1989

Effects of epidural electrical stimulation modalities on spinal cord function and morphology in cats.

The safety of direct electrical stimulation to the spinal cord as used in spinal cord monitoring is controversial. This investigation was undertaken to determine the critical condition of continuous electrical stimulation over a period of 30 min with varying intensities and pulse durations, and the level of safety of intermittent stimulation of 100 pulses with 10 mA current of 0.3 msec duration with varying resting intervals. The spinal cord was evaluated by spinal cord evoked potentials (SCEP) recording and histological examination. The intensity of continuous stimulation greater than 10 mA of 0.3 msec duration resulted in permanent changes in SCEP, focal colliquative necrosis of the cord, and acceleration of the permeability of the intrinsic vessels. In the intermittent stimulation with 1-min resting intervals, spinal cord lesions were not observed.

Action Potentials↗
PubMed1989

[Role of polymorphonuclear leukocytes and oxygen-derived free radicals in the formation of gastric mucosal lesions induced by platelet-activating factor].

Gastric hemorrhagic erosions were induced by the administration of platelet-activating factor (PAF). Gastric wall blood flow was decreased and thiobarbituric acid (TBA) reactants in the gastric mucosa were increased 10 min after PAF injection. SOD and catalase reduced gastric mucosal lesions and TBA reactants, but had no influence on gastric blood flow. In polymorphonuclear leukocytes (PMN)-depleted rats, gastric mucosal lesions and TBA reactants in the gastric mucosa were reduced and gastric blood flow were increased. PAF induced the superoxide production from rat PMN in a dose dependent manner. These results suggest that oxygen-derived free radicals produced by PMN and lipid peroxidation may play an important role in the pathogenesis of gastric mucosal injury induced by PAF.

Animals↗
PubMed1989

[Development and evaluation of ventricular assist blood pump to salvage patients with profound heart failure].

One of the most important characteristics of a ventricular assist device (VAD) is good antithrombogenicity such that the circulating blood does not clot on the surface even when the bypass flow through the device is reduced at the time of weaning-off. A pneumatic and diaphragm-type VAD with excellent antithrombogenicity was developed for clinical use. The pump is made of Japanese-made segmented polyether polyurethane and the maximum output is 7.0 L/min. If the bypass flow was maintained above 2.0 L/min during early postoperative period, thrombus formation was rarely observed even when the flow rate decreased afterwards in chronic animal experiments using 30 goats. Experimental analyses suggested that a biolization mechanism of the material surface covered by absorbed plasma protein might play a major role in the establishment of antithrombogenicity of the pump. No mechanical failure, thrombosis, calcification, and complication in experimental animals occurred when the VAD manufactured under our good quality control system was driven adequately. These results proved that the VAD could be used reliably for at least 3 months. In conclusion, the VAD is safely applicable to clinical cases and contributes to treatments of profound heart failure patients.

Acute Disease↗
PubMed1989

[Experimental studies of prolonged circulatory maintenance with a left ventricular assistance in cardiac arrested goats].

Recently, various types of left ventricular assist systems (LVAS) have become available to treat the patients in profound heart failures beyond the limit of the effects of IABP. However, the occurrence of an intractable severe bi-ventricular failure, ventricular fibrillation (VF) or cardiac arrest during the time with left ventricular assistance became a more serious problem. Since during the usage of these assist devices, pulmonary venous return will decrease, consequently, LVAS will not be able to maintain sufficient systemic circulation over a extended duration. This study was intended to develop a method of prolonged circulatory maintenance only with a LVAS in cardiac arrested goats until the time when heart transplantation will be performed. In this study, our LVAS was implanted between the left atrium and the aorta in twelve goats in which the hearts were fibrillated. We have followed the principle of circulatory maintenance only with our LVAS in cardiac arrest based on the pressure gradient between the right and left atria and at the same time the pump suction effect through the lungs. The results showed that when pulmonary vascular resistances (PVRs) were kept within normal ranges (less than 15,000 dynes.sec.cm-5), systemic circulations were well maintained only with LVAS as long as RAPs were kept in 14-18 mmHg. Under these conditions, the systemic circulatory flows have fluctuated between 80-140 ml/kg/min depending on the animals demands. The mean arterial pressures were kept above 80 mmHg and the goats have shown quite normal behaviors. However, in goats which showed the presence of pleural effusions and ascites were found to be more difficult to maintain prolonged normal circulation. In our study, the maintenance of total serum protein level above 6.0 g/dl was found to be essential to prevent the development of both pleural effusions and ascites . The authors have achieved the longest survival goat for a duration of 38 days after implantation with our LVAS. We have concluded that when PVRs may be kept in normal ranges, our LVAS can maintain normal systemic circulation even in arrested hearts for a prolonged duration during which time heart transplantation or total artificial heart replacement can be performed.

Animals↗
PubMed1989

[A clinical study of a multiregression analysis on the NK activity and related clinical factors in patients with lung cancer].

Using 24 lung cancer patients (20 males and 4 females) who had received radiotherapy, a multivariate analysis has been performed in relation to 19 factors suspected of exerting an effect on natural killer (NK) cell activity. As influencing factors, two factors of the disease, the stage (p less than 0.05) and the leukocyte count (p less than 0.08), were calculated to be significant. In the univariate analysis, the NK activity was found to be significantly low (p less than 0.05) when the leukocyte count was 7,000 or higher. In addition, patients who had died during the course of radiotherapy showed an NK activity which was significantly lower (p less than 0.05) than the activity manifested in both the disease-free patients and the relapsed progressive disease patients. Moreover, the patients with a PS of 40% or less had a significantly lower NK activity than the patients with a PS of 50% or more, though no correlation was found between the NK activity and the disease stage. In the use of this radiotherapy, the NK activity was found to be more strongly influenced by the size of the irradiated field than by the irradiated dose.

Adult↗
PubMed1989

Prerequisites to salvage profound biventricular failure patients with ventricular assist devices.

We conducted chronic experiments to determine how to treat profound biventricular failure systematically with ventricular assist devices (VADs) and to analyze the factors that affect prognoses for this condition. Anoxic arrest was induced in ten goats by aortic cross-clamping under normothermic conditions (38.5 degrees C) for 30 (n = 3), 45 (n = 1), and 60 (n = 6) minutes. A left ventricular assist device (LVAD) was implanted in eight animals, and a biventricular assist device (BVAD) was used in two. Three goats--two of which had undergone anoxic arrest for 30 minutes and one for 60 minutes--whose right atrial pressure (RAP) was approximately 18 mm Hg during the acute stage, recovered in two to three weeks, and the pumps were successfully removed. Pathological findings in these animals showed scattered areas of surviving myocardium, with connective tissue replacing the degenerated myocardium. The remaining five LVAD goats required higher RAPs to maintain circulation and died from various causes. Maintaining circulation without volume loading, even in the presence of arrhythmias, was easier with the BVAD. One BVAD animal that underwent 45 minutes of anoxic arrest recovered from right ventricular failure, and the right pump was removed. The second goat (anoxic arrest, 60 min) on the BVAD failed to recover. Autopsy of the myocardium revealed a thin ventricular wall. Our studies show that the use of VADs allows time for a failing heart to recover, but the potential for healing is affected by the severity of myocardial damage prior to VAD application.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Particle deposition efficiency of therapeutic aerosols in the human maxillary sinus.

The deposition efficiency of therapeutic aerosol particles in the human maxillary sinus is evaluated both in the human body and in a model cast of the upper airway. In the experiments, three sample materials, such as mono-dispersed polystyrene latex particles, aqueous glucose solution and pure water, in the range of particle diameter of from 0.5 to 15.8 microns, are employed in the model cast. The radioactive labelled aerosol particle is also used in the human body. From the results of the experiment, it is confirmed that even though the maxillary sinus is a closed hollow organ, aerosol flow is able to be induced only when the pressure gradient is applied between the nasal cavity and the maxillary sinus. In this case, the particle deposition is is explained in relationship to the inertia impaction of the aerosol particles on the inside wall of the maxillary sinus. The total deposition efficiencies and the deposited particle sizes in the sinus area for both experiments, with the model and in the human body, are almost the same at 3%, and 3-10 microns in diameter, respectively. A physical model for this particle deposition suggests that these experimental values change not only with the size distributions of therapeutic particles and the pressure gradient, but also with the diameter of the sinus ostium. Moreover, since the therapeutic particle might not enter the maxillary sinus when the diameter of the sinus ostium canal is less than 1 mm, some pretreatment to open the sinus ostium canal would be necessary before applying such aerosol therapy in practice.

Aerosols↗